Your first objective in the mistlands should be to get some Seeker Meat, Hare Meat, Yggradasil Wood and Jotun Puffs. Your first objective SHOULD NOT BE FINDING A BLACK CORE OR DVERGR EXTRACTOR.

Get those resources and make the new Pickaxe, and the new foods (Meat Platter, Misthare Supreme) and come back with around 30 more HP and the better pickaxe. Then you can look into getting the 5 black cores you need for the Black Forge. This will allow you to build Kromm and the Arbalest. Both of these weapons should allow you to instantly kill a Dvergr with a sneak attack, but pick your battle wisely. Ideally you should be looking for a Dvergr Dock with a Dvergr Component inside. Normally there's only 1 or 2 Dwarves there, Sneak Attack instakill the Mage (If present).

You could also use Pufferfish cheese.

To Sneak attack kill a Dvergr, just get behind him and do the middle mouse button secondary attack. It's triple damage, and Kromm already hits like a truck, strapped to a tank, delivered by a W-8 Thermonuclear warhead.